iOS之iPhoneX和iOS11适配

1、缺少iPhone X的启动图

在 xcassets 中添加LaunchImage，他里面就会出现 iPhoneX的启动图。

2、导航栏的自定义返回按钮样式不对(主要分两种）

a、自定义backBarButtonItem

backBarButtonItem 的图片会很怪异，这是在iOS 11时改变了里面的布局，使用下面的代码可以解决.

@implementation UIViewController (CustomBackBarButtonItem)

- (void)customBackBarButtonItem {
    if (@available(iOS 11.0, *)) {
        UIImage *image = [[UIImage imageNamed:@"ic_return"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
        UIBarButtonItem *backButtonItem = [[UIBarButtonItem alloc] initWithTitle:@""
                                                                           style:UIBarButtonItemStylePlain
                                                                          target:nil
                                                                          action:nil];
        self.navigationItem.backBarButtonItem = backButtonItem;
        self.navigationController.navigationBar.backIndicatorImage = image;
        self.navigationController.navigationBar.backIndicatorTransitionMaskImage = image;
    } else {
        UIBarButtonItem *backButtonItem = [[UIBarButtonItem alloc] initWithTitle:@""
                                                                             style:UIBarButtonItemStylePlain
                                                                            target:nil
                                                                            action:nil];

        UIImage *image = [UIImage imageNamed:@"ic_return"];
        UIImage *highlightedImage = [UIImage imageNamed:@"ic_return"];
        [backButtonItem setBackButtonBackgroundImage:[image resizableImageWithCapInsets:UIEdgeInsetsMake(0, image.size.width, 0, 0)] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
        [backButtonItem setBackButtonBackgroundImage:[highlightedImage resizableImageWithCapInsets:UIEdgeInsetsMake(0, image.size.width, 0, 0)] forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
        [backButtonItem setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60) forBarMetrics:UIBarMetricsDefault];
        self.navigationItem.backBarButtonItem = backButtonItem;
    }
}

b、自定义leftBarButtonItems

在iOS 11下面我们怎么也无法正常的把返回的按钮尽可能的往左靠近，他就是那么坚挺的偏右，使用下面的方法解决.

UIBarButtonItem *rightBarItem = [[UIBarButtonItem alloc] initWithImage:self.configuration.moreItemImage style:UIBarButtonItemStylePlain target:self action:@selector(onTappedMoreItem:)];
  self.navigationItem.rightBarButtonItem = rightBarItem;

  UIView *backView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 44.0)];
  UIButton *backBtn = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 44.0, 44.0)];
  [backBtn setImage:self.configuration.backItemImage forState:UIControlStateNormal];
  [backBtn addTarget:self action:@selector(onTappedBackButton:) forControlEvents:UIControlEventTouchUpInside];
  [backView addSubview:backBtn];
  if (@available(iOS 11.0, *)) {
      backBtn.contentEdgeInsets = UIEdgeInsetsMake(0, -20, 0, 0);
      backBtn.imageEdgeInsets = UIEdgeInsetsMake(0, -20, 0, 0);
  }

  UIButton *closeBtn = [[UIButton alloc] initWithFrame:CGRectMake(40.0, 0, 44.0, 44.0)];
  closeBtn.hidden = YES;
  [closeBtn setImage:self.configuration.closeItemImage forState:UIControlStateNormal];
  closeBtn.titleLabel.textAlignment = NSTextAlignmentLeft;
  [closeBtn.titleLabel setFont:[UIFont systemFontOfSize:14.0]];
  [closeBtn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
  [closeBtn addTarget:self action:@selector(onTappedCloseButton:) forControlEvents:UIControlEventTouchUpInside];
  [backView addSubview:closeBtn];
  self.closebutton = closeBtn;
  if (@available(iOS 11.0, *)) {
      closeBtn.contentEdgeInsets = UIEdgeInsetsMake(0, -20, 0, 0);
      closeBtn.imageEdgeInsets = UIEdgeInsetsMake(0, -20, 0, 0);
  }

  UIBarButtonItem *leftBarItem = [[UIBarButtonItem alloc] initWithCustomView:backView];
  UIBarButtonItem *spaceButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
  spaceButtonItem.width = -20.f;
  [self.navigationItem setLeftBarButtonItems:@[spaceButtonItem, leftBarItem]];

主要是的起作用的代码是

if (@available(iOS 11.0, *)) {
      backBtn.contentEdgeInsets = UIEdgeInsetsMake(0, -20, 0, 0);
      backBtn.imageEdgeInsets = UIEdgeInsetsMake(0, -20, 0, 0);
  }

3、tableView

磨人的小妖精呀，基本上项目中遍地都是tableview，但是这次她出了问题！

a、groupe 样式下的 setion header \ footer 高度很大，解决办法

_tableView.estimatedRowHeight = 0;
_tableView.estimatedSectionHeaderHeight = 0;
_tableView.estimatedSectionFooterHeight = 0;

b、push 动画进来的时候，会有明显的从下往上偏移的动画，解决办法

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if (@available(iOS 11.0, *)) {
   _tableView.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever;
}

c、有时候 UITableView 与他里面的容器view (UITableViewWrapperView）大小不一致，不管你怎么调整tableveiew的
布局，死活是莫名其妙的有 20 的差距，使用下面的代码解决(这个不是iOS 11的适配，反而ios 11 下面没有)

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if ([self respondsToSelector:@selector(automaticallyAdjustsScrollViewInsets)]) {
    self.automaticallyAdjustsScrollViewInsets = NO;
}

4、搜索框调整

iOS 11 使用新方法将搜索框附着到导航栏上。它需要把UISearchController赋值给navigationItem，看下面的代码

self.searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
self.searchController.searchResultsUpdater = self;
self.searchController.delegate = self;
self.searchController.dimsBackgroundDuringPresentation = NO;
self.searchController.hidesNavigationBarDuringPresentation = NO;

self.searchController.searchBar.barTintColor = [UIColor colorWithRGB:0xf0f0f0];
self.searchController.searchBar.placeholder = @"搜索";

// 重要：参考 http://www.cocoachina.com/ios/20160805/17298.html
self.definesPresentationContext = YES;
if (@available(iOS 11.0, *)) {
   self.navigationItem.searchController = self.searchController;
} else {
   self.tableView.tableHeaderView = self.searchController.searchBar;
}

5、导航栏的高度

对于需要计算顶部高度的地方，应该动态获取状态栏和导航栏高度：


// 动态获取状态栏高度
CGRect statusRect = [[UIApplication sharedApplication] statusBarFrame];
// 动态获取标题栏高度
CGRect navRect = self.navigationController.navigationBar.frame;
CGFloat topHeight = statusRect.size.height + navRect.size.height;

对于需要计算 iPhone X 底部 homeIndicator 高度的地方，可以使用下面的代码：


// 方法一：
CGFloat bottomHeight = 0;
if (@available(iOS 11.0, *)) {
    bottomHeight = [#ViewController#.view safeAreaInsets].bottom;
}

// 或方法二：
#define IS_iPhoneX ([UIScreen mainScreen].bounds.size.height == 812.0)
if (IS_iPhoneX) {
    bottomHeight = 34.f;
}

对于使用 Masonry 写 autoLayout 的，可以像下面这样：

[self.webView mas_makeConstraints:^(MASConstraintMaker *make) {
   make.leading.mas_equalTo(0);
   make.trailing.mas_equalTo(0);
   make.top.mas_equalTo(0);

   if (@available(iOS 11.0, *)) {
       make.bottom.mas_equalTo(weakSelf.view.mas_safeAreaLayoutGuideBottom);
   } else {
       make.bottom.mas_equalTo(0);
   }
 }];

总结

目前基本上主要也就是这些地方需要适配，对于那些支持横屏的应用，那就要多少考虑一下安全区域了，如果只是竖屏应用，其实只要解决好
tableview的安全适配基本上就没有什么问题了。